Gasoline powered hammer



6, 1968 H. v. PFETZING 3,395,688

GASOLINE POWERED HAMMER Filed April 14, 1966 3 Sheets-Sheet l UUUUU x uuu-um 24 INVENTOR HE NRY V. PFETZ I NG ATTORNEY g- 1968 H. v. PFETZING 3 5 GASOL INE POWERED HAMMER Fled Aprl 14, 1966 3 s t h t 2 INVENTOR HENRY V. PFETZING BY ,K W

26.; A'ITORNEY A\lg- 6, 1968 H. v. PFETZING GASOLINE POWERED HAMMER 3 Shets-Sheet 3 Filed April 14. 1966 INVENTOR HE NRY V. PFETZ ING TIG. .9

ATTORNEY United States Patent ice 3,395,688 GASOLINE POWERED HAMMER Henry V. Pfetzing, Michigan Center, Mich., assignor to Skil Corporation, Cook County, Ill. Filed Apr; 14, 1966, Ser. No. 542,508 17 Clans. (Cl. 123-180) The invention pertains to a percussive device, and particularly relates to an internal combustion percussive device of the hammer type.

The invention constitutes improvements on the percussive devices shown in United States Patents 3,012,549 and 3,046,958. Percussive devices of the type shown in the aforementioned patents utilize a gaseous fuel which is ignited to translate a piston to produce a working, or impact, stroke. Percussive devices of this type have the advantage over the more conventional air hammer in that expensive auxiliary equipment such as air compressors are not required and the device is selt-contained.

As a percussive device of the type of the invention utilizes a fioating piston wherein the movement of the moving Components is linear, the starting of such devices requires auxiliary fuel compression means. In the aforementioned patents, starting of the devices is produced by injecting a fuel mixture into the combustion chamber by means of a manual pump arrangement. The starter fuel injected into the combustion chamber is ignited to produce the initial movement of the piston. Recoil and piston biasing means are utilized to :return the piston to the fuel compressing position after the initial manual compression of the starter fuel and the device will thereafter compress its fuel, ignite and move the piston through the operative cycle automatically. e

As the starting of such percussive devices using a manually compressed starter fuel system requires that the operator attend to several matters manually, such as choking the carburetor, actuating a starting fuel ignition circuit, and Operating the pump, the starting of this type of internal combustion percussive device is somewhat complicated and troublesome. It is a basic -object of the invention to provide an internal combustion percussive device wherein the starting procedure is substantially simplified with respect to similar devices of this'type and the opportunity for improper starting operation by the operator is minimized. i

Another object of the invention is to provide an internal combustion percussive device utilizing a manually operated starter fuel compression pump and a choke wherein choking of the carburetor is automatically regulated in accordance with the operation of the starterfuel compression pump.

A further object of the invention is to provide an internal combustion percussive device utilizing a fuel ignition starter circuit switch and a .starter fuel compression pump wherein the starter ignition switch is automatically actuated by and related to the position and phase of operation of the starter fuel compression pump.

Yet another objectof the'invention is to provide an internal combustion percussive device employing a chokeable carburetor, a starter fuel igntion circuit, and a starter fuel compression pump wherein operation of the compression pump automatically actuates the carburetor choke and the starter fuel ignition circuit.

An additional object of the invention is to provide an internal combustion percussive device utilizing a starter fuel compression pump and a chokeable carburetor wherein the pump includes a manually reciprocal piston and the position of the carburetor choke is determined by both the reciprocal position of the piston within the pump and the rotative position therein.

Yet another object of the invention is to provide a starting and fueling unit for an internal combustion precussive 3,395,688 Patented Aug. 6, 1968 device wherein the starting and fueling unit may be ernployed with percussive devices currently in use and wherein such units are of a more concise size and employ a less complicated sequence of starting operation than known starting and fueling systems with this type of percussive device.

These and other objects of the invention arising from the details and relationships of the Components of an embodiment thereof will be apparent from the following description and accompanying drawings wherein:

FIG. 1 is a perspective view of an internal combustion percussive device in accord with the invention,

FIG. 2 is an enlarged, elevational view of the starting and fuel Components of the invention, a portion of the fuel tank being cut away for purposes of illustration,

FIG. 3 is an elevational, sectional View of a percussive device in accord with the invention, the starter pump piston being shown in an intermediate position within its cylinder,

FIG. 4 is an elevational, sectional view through the manifold as taken along section IV-IV of FIG. 3,

FIG. 5 is a detail, elevational, sectional View of the starter fuel pump, carburetor and choke structure illustrating the carburetor in the choked and running position,

FIG. 6 is an elevational, sectional view similar to FIG. 5, illustrating the piston in a position opening the choke of the carburetor,

FIG. 7 is a plan, sectional view through the starter fuel ignition switch showing the switch in the closed fuel ignition energizing position, as taken along section VII-VII of FIG. 3,

FIG. 8 is a plan, sectional View similar to FIG. 7, illustrating the relationship of the Components when the fuel ignition switch is open, 'and FIG. 9 is a plan, detail, sectional view of the fuel ignition breaker points and actuator taken along section IX-IX of FIG. 3.

The percussive device in accord with the invention includes a combustion cylinder, tool holding assembly generally indicated at 10. The upper portion 12 of the assembly 10 is provided with a combustion cylinder 14 having an exhaust port 16 defined therein. A fuel inlet port 18 is defined in the portion 12 at a vertical location corresponding to the exhaust port and at thereto. The assembly 10 is also provided with a cylindrical cylinder portion 20` of a greater diameter than the combustion cylinder 14 and is concentric thereto. An annular piston recoil pad assembly 22 is mounted in the assembly 10 at the area of the' joining of portion 12 with the lower portion 24 of the assembly. The recoil pad 22 serves to cushion the piston stroke and return the piston, and the structure of the pad 22 forms the subject matter of my copending United States application Ser. No. 542,642, filed Apr. 14, 196 6, now abandoned. Portion 24 is provided with the bore 26` for receiving the piston biasing spring 28. A tool-holder assembly 30 is mounted at the lowermost end ot the percussive device assembly 10,and includes an adaptor 32 adapted to receive the upper end of a tool 34. The tool upper end projects into the bore 26, as will be apparent from FIG. 3. The portion 24 of the assembly 10 is aflixed to the upper portion 12 by bolts 36 which permit assembly of the recoil pad, piston, and other internal components.

A floating piston 38 is reciprocally mounted within the assembly 10. The piston 38 includes a head portion 40 which has grooves defined thereon adapted to receive piston rings 42 whereby an effective combustion chamber is defined by the piston head and the upper portion of the combustion cylinder 14. The piston 38 is of a smaller diameter at 44 and is formed with an annular conical surface 46 for cooperation With ignition timing means as will be later described.

The piston 38 is provided with an annular flange 48 adapted to have a sliding scaling engagement With the cylinder 20. The recoil pad 22 is formed with a central cylinder bore through which the piston cylindrical wall 50 extends and is guided by a wiper ring 52 mounted upon the recoil pad. The compression spring 28 interposed between the lower end of the piston 38 and the lower end of the assembly bore 26 biases the piston in an upward direction and is of sufiicient strength to maintain the piston in its uppermost position, as illustrated in FIG. 3. The piston portion 5.4 comprises an anvil adapted to strike the upper end ot the tool 34 at the end of the downward, or Working stroke, of the piston.

The upper portion of the assembly is provided with a threaded opening 56 cooperating with a starter fuel injection orifice 58 which communicates with the uppermost portion of the combustion 'cylinder 14. A conventional spark plug 60 is also mounted upon the assembly 10 having ignition points communicating with the upper portion of the cylinder 14.

A fuel-receiving orifice is defined in the assembly 10 at 62. The orifice 62 communicates with the cylinder adjacent the recoil pad and, as will later be described, communicates with the carburetor mixed fuel passage. A passage 64 is defined in the assembly portion 24 communicating with bore 26 and is adapted to provide cooling air to the spark plug and the upper exterior portion of the combustion chamber. Also, for cooling purposes, an opening 66 is defined in the assembly 10 to permit atmospheric air to be drawn into the cylinder 20 above the flange 48 as the piston 38 moves downwardly.

A pair of upright members 68 are affixed to the assembly 10 and extend vertically thereabove. A handle 70 is affixed upon the members 68 and an ignition coil 72 and associated ignition structure is mounted upon the uprights 68.

The starting and fuel unit of the percussive device consists basically of a pair of members 74 and 76 which may be fastened together, or cast in one piece, if desired. The body member 74 is adapted to be aflixed to the assembly 10 by bolts 7-8 and these bolts extend through the manifold member 76. The supporting body member 74 constitutes the support for a U-shaped fuel tank 80. The fuel tank 80 includes vertically disposed leg portions 82 interconnected by an arcuate base portion 84. One of the upper terminating ends of the fuel tank leg portions is sealed and the other terminating end is provided with a removable cap 86, whereby fuel may be placed in the tank. A tubular handle and equalizng Conduit 88 communicates with leg portions 82. A fuel outlet is formed at 90 in the tank base portion whereby a fitting permits the fuel to be withdrawn from the tank and fed to the carburetor. The fuel outlet 90 includes the fitting 92 having a flexible hose 94 provided with a filter element at its end which seeks the lowermost part of the tank, wherein it is insured that the entire amount of fuel is available to the carburetor even though the device may be inclined at a substantial angle, as is the usual practice during use.

The member 74 includes a vertically disposed cylinder 96 defined therein which constitutes the cylinder of the starting pump. The cylinder 96 is provided with a cap 98 at its upper end, and the cap is provided with an opening through which the piston rod 100 of a piston 102 extends. "The upper end of the piston rod 100` includes a handle 104 whereby the piston may be manually positioned within the cylinder 96. The piston 102 is connected to the lower end of the piston rod 100 by a nut 106, whereby the piston and piston rod are fixed relative to each other. The lower surface of the piston 102 is provided with a projection 108 extending below the surface 110 of the piston. The projection 108 and the surface 110 are separated by a pair of inclined surfaces 112 disposed adjacent the periphery of the piston, one of which is shown in FIG. 3. The configuration of the projection 108 is such that the projection 108 and the surface each comprises approximately l80 of the piston lower area.

An ignition starter switch for the energization of the spark plug 60 during the starting operation is mounted within the cylinder cap 98. The cap 98 includes a cover 114 removably afiixed to the cap base 116. The cap base is recessed at 118 to provide clearance for a pair of levers 120 pivotally mounted upon the base by pivot pins 122. Thus, the levers 120 may move in a horizontal plane, FIG. 3, toward and away from the piston rod 100. A leaf spring 124 bears upon the levers 120 tending to bias the levers inwardly toward engagement with the piston rod. A contact pin 126 extends through a bore 128 defined in the cap base into the recess 118 and is supported by a leaf spring 130 which is insulated from the base by a dielectric strip 132. A fastener 134 holds the spring 130 and strip 132 on the base 116 and a conductor 136 is connected to spring 130.

The piston rod 100 is provided with a pair of diametrically opposed flats 138. The flats 138 are axially positioned on the piston rod such that when the piston pnojection 108 is engaging the :bottom surface 140 of the cylinder 96, as in FIGS. 5 and 6, the fiats will be in alignment with the levers 120. Thus, upon rotat-ing the piston rod 100 whereby the flats 138 are parallel to the inner surfaces of the levers, the spring 124 will bias the levers into engagement with the flats to the position shown in FIG. 8. In this position, the lever 120 nearest the contact pin 126 will be out of engagement with the pin. When the piston rod 100 is raised, as shown in FIG. 3, the flats 138 will be out of alignment with the levers 120, and the engagement of the levers with the piston rod biases the levers outwardly which causes the lever 120 adjacent the contact pin 126 to engage the contact pin and deflect the leaf spring 130, as in FIG. 7. The engagement of the lever 120 and the contact pin 126 completes a grounding circuit to the spark plug 60 which causes continuous energization, or ignition, of the spark plug.

At the lower end of the body 74, a carburetor 142 is mounted. The carburetor 142 includes the conventional air passage therethrough, whereby air may enter the carburetor at the bottom and as the air is drawn upwardly through the carburetor, fuel provided to the carburetor through the hose 94 and conduit 144 is mixed with the air to provide a fuel mixture. Preferably, the canb-uretor is of the type manufactured by the Tillotson Company which includes a diaphgram sensing the pulsation of the air as it is drawn into the carburetor. The pulsating diaphragm functions as a fuel pump to draw the fuel from the fuel tank into the carburetor. The carburetor 142 also includes a choke of a conventional type pivotally mounted in the carburetor threat on a shaft 146. However, the usual biasing means associated with the coke is related to the choke position so that the spring biasing means biases the choke toward the fully closed or choked' position.

A choke rod 148 is associated with the carburetor shaft 146 and is received within an enlarged clearence opening 150 defined on the lower end of the body 74. A smaller bore 156 is defined in the body 74 which intersects the cylinder bottom 140 and wall such that the upper end 154 of the choke rod 148 slidably extending through the bore 156 is located within the cylinder adjacent the lower wall thereof and may be selectively engaged b-y the projection 108 defined upon the piston 102.

The lower end of the body 74 is provided with a mixed fuel passage 158 having a reed valve 160 defined therein. The passage 158 communicates With the manifold passage 162 which in turn communicates with the bore 62.

Another fuel passage 164 is defined :between the passage 158 and the cylinder 96. The passage 164 is unidirectional, in that a check valve 166 is located therein permitting flow of fuel mixture only from the passage 158 to the cylinder.

5. The carburetor 142 is located in the chamber 168 defined between the leg portions of the fuel tank. This chamber is sealed at the back by a plate 170 welded to the fuel tank. The front portionof the chamber is sealed by a plate 172 which has openings 174 defined therein. An annular air filter 176 is disposed between the plate 172 and a retainer cover 178. The cover 178 is held upon the air filter by a wing nut assembly. In this manner, air drawn into the chamber 168, for mixture with the fuel, is filtered by the air filter 176.

The manif-old'member 76 is provided with a starter fuel receiving passage 180. The passage 180- communicates at its lower end with the lower portion of the cylinder 96. The upper portion of the passage 180 communicates with a starter fuel injection plug 182 adapted t-o thread into the opening 56 defined in the upper portion -of the assembly 10. The plug 182 is provided with an aXial bore and includes radial bores communicating with the outer surface of the plug. Thus, starter fuel within the passage 180 may be injected into the plug 182 and into the orifice 58 and combustion chamber. A ball check valve 184 is received within the passage 180 adjacent plug 182 and cooperates with a conical seat, preventing combustion gases from entering the passage.

The manifold 7 6 also includes a cooling air passage 186 having an outlet at 188 adapted to eject cooling air across the top of the assembly 10 to cool the combustion chamber and spark plug. The lower end ofthe passage 186 communicates with a passage 190 formed in portion 24 which communicates with a chamber 192 receiving a reed valve 194. The block 196 includes a passage 198 communicating with the passage 190, whereby compressed cooling air may enter the passage 198 and open the reed valve 194 for ejection into the passage 186 and across the top of the assembly 10. An air intake passage 200 is defined in the portion 24 which oommunicates with the chamber 202 through which reed valve 204 is mounted. The passage 200 communicates with the atmosphere whereby air may be drawn into the passages 198 and 64 when the piston is moving in an upward or fuelcompressng direction and expelled from bore 26 through passages 64, 198 and 186 during the working stroke.

A running fuel passage 206 is defined in the manifold 76 communicating with the orifice 62. The passage 206 communicates with a manifold 208 'affixed to the side of the assembly 10 for conveying fuel entering the passage 206 to the fuel port 18 defined in the assembly portion 12.

During normal running the timing of the firing of the spark plug is determined by ignition contact points 210 which are operated by a plunger 212 slida'oly received within a .bore 214 defined in the assembly portion 12. The plunger 212 engages the movable contact of the contact points 210 and is biased by the spring of the contact points, which are of the automotive type, toward the piston 38. The innermost portion of the plunger rides upon the piston portion 44 and, upon the piston 38 being downwardly defiected during a working stroke sufficiently to permit the plunger to be engaged Aby the conical surface 46, the conical surface will defiect the plunger outwardly to open the points 210. The position of the plunger 212 is such that opening of the contacts 210 upon engagement with the piston surface 46 with the plunger provides the proper timing of ignition of the spark plug to produce operation of the device.

In operation, the operator will turn a manually-operated ignition switch 216 to the on' position. Of course, a battery, or electrical power source, is associated with the ignition circuit to provide the necessary electrical energy. In the normal position -of the components at the beginning of the starting cycle, the piston 38 will be in its uppermost position, as shown in FIG. 3, due to the biasing action of spring 28. The starter piston 102 will 'be in its lowermost position and will be rotated relative to the cylinder 96, whereby the relationship shown in FIG. 6 will exist. After turning on the ignition switch 216, the

operator will grasp the starter piston handle 104 and rotate the handle 180 to position the piston' relative to the choke rod 148, as shown in FIG. 5. In this position, the choke rod 148 will be biased upwardly by its spring as the projection 108 has now been rotated out of alignment with the rod end 154 and the difference in aXial position of the projection 108 and the piston surface 110 permits the rod to move upwardly. In the position of FIG. 5, the carburetor 142 will be in its fully choked condition.

The operator now pulls upwardly upon the piston rod 100. Upward movement of the piston 102 draws a gas and air mixture from the passage 158 into the cylinder 96 through passage 164. As the reed valve 160 will be closed, the vacuum created within the cylinder 96 will draw air through the carburetor to draw a fuel mixture into the cylinder. Simultaneously, raising of the piston rod fiats 138 relative to the levers 120, biases the levers 120 to the position shown in FIG. 7. Contact of the assocated lever 120 and the contact pin 126 bypasses the ignition circuit controlled by the ignition contact points 210 and operates a vibrator component in coil 72 to cause a continuous spark to occur in the combustion chamber.

After the piston rod 100 has been drawn upwardly, the operator quickly pushes down on the piston rod to compress the fuel mixture within the cylinder 96. Compression of the fuel mixture within the cylinder 96 forces the fuel mixture into the passage 180, raising the check valve 1 84, and injects the fuel mixture into the combustion cylinder 14. The existence of the continuous spark within the combustion cylinder permits the starting fuel charge to ignite as soon as a combustible mixture is received within the combustion chamber. Ignition of the fuel within the combustion cylinder 14 drives the piston 38 downwardly. The piston 38 will move downwardly until the flange 48 engages with recoil pad 22, and the piston anvil 54 engages with the top of the tool 34. In that the recoil pad 22 includes a plurality of sprngs 218, the fiange 48 will bounce from the recoil pad and move the piston in an upward direction. Such movement of the piston 38 draws fuel mixture into the cylinder 20 through the orifice 62 and passage 162, which is injected into the cylinder 14 at the end of the next working stroke.

If the engine has not started a running cycle upon the first depression of the piston 102, the piston rod 100 is again raised and the previously described starting cycle repeated. As the second firing within the combustion chamber forces the piston 38 down, the fuel mixture with the cylinder 20 will be forced therefrom by the flange 48 and forced into the combustion chamber 14 upon the piston 38 uncovering the fuel port 18 in the normal manner in the operation of a two-cycle internal combustion engine. Thus, as soon as the exhaust port 16 is exposed to the combustion chamber due to the downward position of the piston portion 40, the fresh fuel will enter the combustion chamber and as the piston moves upwardly, this fuel is compressed and ignited. When the device i s cold, usually two or three pumps of the piston rod 100 -are sufiicient to initiate continuous operation. When the engine is warm, only a single -pump of the piston rod is usually required.

Once the engine has started to cycle, the operator will fully depress the piston rod and piston 102 to the position shown in FIG. 5. In this position, the ignition starter switch will be opened, as in FIG. 8, and the ignition of the spark plug will now be controlled by the contact points 210. In that the piston lower surface 110 is -in alignment with the choke rod end 154, the carburetor will still be in the fully choked position. After the device has had an opportunity to warm up, the operator turns the piston rod handle 104 to position the projection 108 over the choke rod end 154, as shown in FIG. 6. This position depresses the choke rod 148 to fully open the h k d permits the device to operate in its most eflicient mannetr.

As the piston 38 rapidly moves up and down ithi the assembly 10 at the lowermost position of the piston,

the anvil 54 will strike the tool 34 to impart a working stroke to the tool. The tool may be provided with a spade, point, chisel, tamp or other implement at its lower end, not shown.

Movement of the piston portion 50 within the assembly bore 26 pumps cooling air from the atmosphere into the passage 186 for injection of the air over the upper portion of the assembly 10 and the spark plug. In this manner, the combustion chamber may be maintained at an aoceptable temperature. The device will continue operating until the main ignition switch is turned ofl.

Percussive devices manufiactured by the assignee's predecessor are currently on the market and utilize a different starting and fueling system than that described, as will be appa rent from the aforementioned patents. However, many of the percussive device models now in use have the opening 56, orifice 62 and passage 64 located `as illustrated. In these models, the starter and fuel unit of the invention can ibe readily substituted for the original starting and fuel Components without modification thereto, other than merely removing the old starter and fueling units and replacng these units with the described Components.

In that choking of the carburetor 142 and operation of the starter gnition switch is automatically operated in dependence upon the position of the piston 102 within the cylinder 96, a minimum of special skill is required by the operation to start the device and once the device is started, merely rotating thes piston rod 180 shifts the choke from a choke position to the hun position. In addition to the levers 12.0 Operating the starter ign'ition system, the cooperation of the levers with the fiats 138 defined in the piston tl'Od act as a detent to maintaining the piston rod in its fully depressed position regardless of the considerable vibration present. In the event the device becomes "flooded" during starting, a manually operated choke lever 220 mounted on carburetor 142 can be used to lock out the choke (Od 148 to permit a greater amount of air to be drawn into the cylinder 96.

It is appreciated that various modifications to the invention may be apparent to those skilled in the art without departing from the spirit and scope thereof, and it is intended that the invention be defined only by the scope of the following claims.

I claim:

1. An internal combustion percussive device comprising, in combination,

(a) a body having a combustion cylinder defined there- (b) a piston within said cylinder adapted to reciprocate between a fuel charge compressing position and an exhaust position,

(c) spring means biasing said piston toward the fuel charge compressing position,

(d) a fueling system including a carburetor having a choke, a fuel tank communicating with said carburetor and a passage establishing communication between said carburetor and said cylinder,

(e) a starting mechanism mounted on said body including a pump having a starter cylinder and a manually operated starter piston reciprocally mounted within said cylinder,

(f) a first passage establishing unidirectional communication between said carburetor and said starter cylinder and a second passage establishing unidirectional communication between said starter cylinder and said combustion cylinder, and

(g) means interposed between said carburetor choke and said starter piston adapted to automatically actuate said choke at a preselected position of said starter piston.

2. In an internal combustion percussive device as in claim 1 wherein:

(a) said starter piston is reciprocally movable in said 8 starter cylinder between a starter cylinder fuel charging position and a starter fuel compression position, said means adapted to automatically actuate said choke closing said choke during movement of said starter piston between said positions thereof,

3. In an internal combustion percussive device as in claim 1 wherein:

(a) said starter piston is mounted within said starter cylinder for rotata-ble movement between first and second positions,

(b) said means adapted to automatically actuate said choke closing said choke at said first' rotative position of said piston and opening said choke at said second rotative position of said piston.

4. In an internal combustion percussive device as in claim 2 wherein:

(a) said starter piston is mounted within said starter cylinder for rotatable movement between first and second positions when said starter piston is at the starter fuel compression position,

(b) said means adapted to automatically actuate said choke closing said choke at said first rotative position of said piston and opening said choke at said second rotative position of said piston.

5. In an internal combustion percussive device as in claim 1 wherein:

(a) said means adapted to automatically actuate said choke includes a choke operatin rod, said rod extending into said starter cylinder, and

(b) choke rod engagement means defined on said starter piston adapted to engage and actuate said choke'rod at predetermined positions of said starter piston within said starter cylinder.

6. In an internal combustion percussive device as in claim 5 wherein:

(a) said choke rod includes an end within said starter cylinder, and

(b) said choke rod engagement means includes a projection defined on said starter piston adapted to selectively engage said choke rod end.

7. In an internal combustion percussive device as in claim 1 wherein:

(a) said device includes a fuel ignition system comprising an electrical fuel igniter within said combustion cylinder,

(b) a voltage source adapted to selectively energize said fuel igniter,

(c) an igniton switch controlling energization of said igniter,

(d) means Operating said ignition switch in accordance with the position of said piston within said combustion cylinder, and

(e) a starter switch adapted to continuously energize said fuel igniter regardless of the position of said piston.

8. In an internal combustion percussive device as in claim 7 wherein:

(a) starter switch actuating means 'are associated with said manually operated starter piston whereby predetermined movement of said starter piston actuates said starter switch.

9. In an internal combustion percussive device as in claim 7 wherein:

(a) said starter piston includes a piston rod, and

( b) starter switch actuating means defined on said piston rod, said starter switch engaging said starter switch actuating means whereby positioning of said starter piston automatically energizes and de-energizes said starter switch.

10. A starting and fueling unit for an internal combustion percussive device having a fuel igniter, a starter fuel injection port and a running fuel receiving orifice comprising, in combination,

(a) a supporting body adapted to be afiixed to a percussive device,

(b) a fuel tank having an outlet and an inlet mounted on said body,

(c) a cylinder defined in said supporting body,

(d) a manually operated piston mounted for reciprocal movement within said cylinder,

(e) a carburetor mounted on said body having a fuel inlet communicating with said fuel tank outlet and a fuel mixture outlet,

(f) a first passage defined in said body communicating with said carburetor fuel mixture outlet and adapted to communicate with the percussive device fuel receiving orifice upon said supporting body being affixed thereto,

(g) a second unidirectionally valved passage interconnecting said first passage and said cylinder permitting fuel mixture flow from said first passage to said cylinder, and

(h) a third passage communicating with said cylinder and adapted to communicate with the Starter fuel injection port upon said supporting body being affixed to the percussive device.

11. In a starting and fueling unit for an internal combustion percussive device as in claim 10 wherein:

(a) said carburetor includes a choke,

(b) choke actuating means operatively associated with said choke, and

(c) means connecting said piston to said choke actuating means at predetermined positions of said piston to actuate said choke.

12. In a starting and fueling unit for an internal combustion percussive device as in claim 10 wherein:

(a) said carbu'etor includes a choke,

(b) a choke rod connected to said choke and extending into said cylinder, and

(c) choke rod engaging means defined on said piston adapted to selectively engage said choke rod and actuate said choke at predetermined positions of said piston within said cylinder.

13. -In a starting and fueling unit for an internal combustion percussive device as in claim 10 wherein:

(a) a fuel gniter ignition switch is mounted on said supporting body, and

(b) means interconnecting said switch and said piston actuating said switch in accordance with the position of said piston within said cylinder.

14. In a starting and fueiing unit for an internal combuston percussive device as in claim 11 wherein:

(a) a fuel gniter ignition switch is mounted on said supporting body, and

(b) means interconnectng said switch and said piston actuating said switch in accordance with the position of said piston within said cylinder.

15. In a starting and fueling unit for an internal combustion percussive device as in claim 12:

'(a) a piston rod connected to said piston,

(b) a fuel gniter switch mounted on said supporting body adjacent said piston rod, and

(c) switch actuating means defined on said piston rod actuating said switch in dependence upon the position of said piston within said cylinder.

16. In a starting and fueling unit for an internal combustion percussive device as in claim 10 wherein:

(a) said fuel tank is of a U-configuration having a pair of tubular leg portions interconnected by a tubuiar base portion,

(b) said tank nlet comprising an opening defined at the terminus of one of said leg portions, and

'(c) said tank outlet being defined in said base portion.

17. In a starting and fueling unit for an internal combustion percussive device as in claim 16 wherein:

(a) said supporting body is located intermediate said fuel tank leg portions.

References Cited UNITED STATES PATENTS 2,744,736 5/ 1956 Evinrude 261-34 3,012,549 12/ 1961 Bard et al 173--134 LAURENCE M. GOODRIDGE, Pr'mary Exam'ner. 

1. AN INTERNAL COMBUSTION PERCUSSIVE DEVICE COMPRISING, IN COMBINATION, (A) A BODY HAVING A COMBUSTION CYLINDER DEFINED THEREIN, (B) A PISTON WITHIN SAID CYLINDER ADAPTED TO RECIPROCATE BETWEEN A FUEL CHARGE COMPRESSING POSITION AND AN EXHAUST POSITION, (C) SPRING MEANS BIASING SAID PISTON TOWARD THE FUEL CHARGE COMPRESSING POSITION, (D) A FUELING SYSTEM INCLUDING A CARBURETOR HAVING A CHOKE, A FUEL TANK COMMUNICATING WITH SAID CARBURETOR AND A PASSAGE ESTABLISHING COMMUNICATION BETWEEN SAID CARBURETOR AND SAID CYLINDER, 